1. Field of the Invention
The present invention relates to a method for smoothing magnetic recording media and device therefor, more particularly to a method for obtaining magnetic recording media of high density and high quality of magnetic particles without any damage thereto by removing a gravure pattern in a coating on the media.
In general, magnetic recording media including magnetic tape such as video tape or the like are coated with magnetic recording solution by means of a coating device and smoothed by a smoothing device in order to make uniform the thickness of the layer of the solution and to orient easily the magnetization axes of magnetic particles contained in said solution in a specific direction and then to treat said smoothed layer of magnetic recording solution by a dryer. That is, the coated magnetic recording solution on a nonmagnetic base is not even in thickness and a smoothing treatment is required. Conventional smoothing treatments such as blade smoothing, doctor smoothing, film smoothing or the like are well known. In these smoothing methods, a layer of coated solution is smoothed by a blade, a doctor or a sheet of film. However, it has been pointed out as drawbacks that several longitudinal lines or bubbles are observed in the direction of movement of the nonmagnetic sheet, otherwise patterns of various stripes are observed depending upon the quality of the solution, if a surplus of said solution is not scraped skillfully. In addition, guide rolls disposed underneath said nonmagnetic base facing a blade or a doctor knife located above the base sometimes cause uneven thickness of the layer of the solution due to imperfectness of the finished dimension of said rolls. In order to eliminate such problems, there has been proposed a method that many magnets are disposed with their magnetic poles alternately arranged. A nonmagnetic base coated with magnetic recording solution on the surface of said nonmagnetic base is slidably placed on the magnets and a layer of the coated solution is smoothed by magnetic fields of said magnets. However, in this case a nonmagnetic base is touched on the surface of the magnets and the nonmagnetic base is inclined to being damaged, particularly when dust causes damages by friction. It is, therefore, desired to eliminate such defects.